| | 4 ~ 8 | 12 | | | | ① | | | ② | | | | | | | | 1. 18 ~ 36 | | | | | | | | | | | | | | | | | 300 ~ 500 0.2％ 0.1％ | 2 ~ 3 | | 2. | | | | | | | | 3. | | 30 50 | | | D | | | | | |